With the rapid progress in networking and computing technologies, a wide variety of network-based computing applications have been developed and deployed on the internet. Flexible and effective service provisioning for supporting the diverse applications is a key requirement for the next generation internet. However, the current internet lacks sufficient capability for meeting this requirement, mainly due to the ossification caused by tight coupling between network architecture and infrastructure. Service-Oriented Architecture (SOA), which has been widely adopted in cloud computing via the Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service (SaaS) paradigms, may be applied in networking to decouple network architecture and infrastructure; thus offering a promising approach to addressing some fundamental challenges to the next generation Internet. In general, such a service-oriented networking paradigm is referred to as Network as-a-Service (NaaS). This book presents the state of the art of the NaaS paradigm, including its concepts, architecture, key technologies, applications, and development directions for future network service provisioning. It provides readers with a comprehensive reference that reflects the most current technical developments related to NaaS.

A fundamental strategy taken by the research for the next generation Internet lies in application of the service-orientation principle in the field of networking, which enables the as-a-Service paradigm that has been widely adopted in cloud computing, for example, Infrastructure-as-a-Service (IaaS) and Software-as-a-Service (SaaS), inside future networking systems. Therefore, such an approach to future network design is referred to as Network-as-a-Service (NaaS). NaaS is expected to play a crucial role in the next generation Internet that may introduce significant changes in both network architecture and service delivery model. The main objective of this chapter is to give a high-level overview of the NaaS concept with its key enabling technologies and to present the significant impact of NaaS on the development of Internet architecture and service model. The author hopes to provide readers with a big picture about the NaaS paradigm and its important role in the next generation Internet together with a holistic vision across networking and cloud computing for future service provisioning.

Network-as-a-Service (NaaS) is fast advancing and it abstracts the heterogeneous and dynamic network resources and their relationships as connected and uniform REST services. This chapter covers the REST service infrastructure for NaaS as well as methods and techniques in REST service modeling and service design for applications in data networking.

This chapter presents Network-as-a-Service (NaaS) architecture leveraged with flexibility and dynamicity. Convergence and stronger collaboration between network planes while keeping separation is the driving notion for this chapter. We first analyze the convergence of the needs and the convergence of conceptual and technological solutions in the new telecommunication ecosystem. We have considered solutions such as Network Functions Virtualization (NFV), Software-Defined Networking (SDN), Cloud and Service-Oriented Architecture (SOA). The advantages brought by these paradigms contribute to the pillars of NaaS. Thus, their convergence and collaboration is necessary for realizing NaaS. However, they present challenges that yet need to be addressed. Therefore, we study the evolution that is crucial for a flexible and dynamic NaaS. We describe an approach for designing Virtual Network Functions (VNFs) as service components. This “as-a-Service” design presents a service component architecture model with functional and non-functional aspects, and a set of properties to be respected for the structure, interconnection and for the management of VNFs. We also describe the importance of adopting and integrating dynamicApplication Programming Interfaces (APIs) in the relational dimension of NaaS for more agility in contracts. These new schemes allow us to introduce flexibility then dynamicity of NaaS. These two NaaS features rely on the interactions of network planes (data, control and management plane). Flexibility is achieved through the offers of network services that can be customized through a network exposition layer. This layer offers discovery, selection and composition of VNFs. These VNFs are first described with quality of service (QoS) information for a QoS-based selection according to the required or desired QoS. The customization is possible thanks to service composition. Dynamicity is achieved through an automated global orchestration of network services. We define the functions of this orchestration after an integration of SDN and NFV, then an incremental integration of SDN-enabled NFV with “as-a-Service,” dynamicAPIs and a new network virtualization layer, all in the same architecture. The global orchestration is responsible for automatic life-cycle management of network services for dynamic Service LevelAgreements (SLAs). Indeed, this automation aims at ensuring compliance of QoS with SLAs and to react as dynamically as the changes in user requests or preferences.

While telecommunication and networking are driven by massive adoption of virtualization and the emergence of network programmability, the process of deployment remains an important phase in virtual networks (VNs) life-cycle. We raise through this chapter the question about the importance and opportuneness of redesigning VN deployment process in this new ecosystem. For that, we have first raised the impacts and advantages brought by Cloud Computing, SoftwareDefined Networks (SDNs) and Network Function Virtualization (NFV) over network architectures and operations. We have then focused on the notion of Network-as-aService (NaaS) which integrates these new technologies. We have come to define the role and the characteristics of NaaS. This way, we have been led to distinguish two issues for the implementation of VNs. The first one is the actual process of deployment of VNs at a network service delivery level that takes into account the applicative flows, and the second one is the placement process at the physical network infrastructure. Our objective is to present the “Virtual Deployment” as a phase within the VN deployment process. We define the virtual deployment phase using NaaS architecture. Our virtual deployment proposition takes into account the properties of flexibility, adaptability and dynamicity that are vital for the NaaS, where Cloud, SDN and NFV represent major building components in operators' network architectures. Thus, the virtual deployment of a VN is meant to integrate a response to a Service Level Agreement (SLA) request. Indeed, it supports the adaptation of a VN to integrate, starting from the deployment phase, network-level Quality of Service (QoS) constraints as a response to the service level agreement (SLA) request. To automate the virtual deployment, we propose to introduce the QoS constraints at the design phase. Therefore, through a Network Application Programming Interface (API), a network orchestrator will be able to consider “On Demand Services” and “User-Controlled services.” Also, we rely on the abstraction of the Network Operating System (NOS) to address the need for an ability to choose and adopt the most efficient network control functions. Thus a personalized VN is consolidated, which takes into account all network constraints coming like requests from SLA and from usage. We end this chapter by presenting technical tools that can be used for this purpose but they still have some limitations. The conclusion highlights the strengths of our proposal and introduces the perspectives.

The next generation Internet is expected to cope with new challenges to support a wide spectrum of network applications with highly diverse requirements due to the coexisting heterogeneous network environment. One of the challenges to achieve this objective lies in enabling network domain collaboration and network application interaction without exposing the internal structure and implementation details of each domain, where network virtualization will play a pivotal role in allowing a large number of service providers to offer various network services upon shared network infrastructure. Service-Oriented Architecture (SOA) [39] offers an effective architectural principle for heterogeneous system integration and provides a promising approach to support network virtualization, which can be applied in network service discovery, selection, and brokerage for the special requirements of future Internet. Due to the heterogeneity of network systems in ubiquitous and pervasive computing environments, network service discovery, selection, and brokerage face one of the main challenges to specify network demands of various applications. A key to solve this problem lies in flexible and effective interactions among the heterogeneous networks, various implementations and ubiquitous architectures with scalable information update, network-platform-independent methods, multi-attribute decision-making techniques, etc.

This chapter introduces the background and characteristics of service selection and recommendation in integrated network. Then it details the scenarios and definitions of service selection and recommendation, analyzes various algorithms, techniques, and strategies of service selection and recommendation, and finally summarizes limitations and evaluation indexes for service selection and recommendation approaches.

On-demand service is the paradigm that reflects the way that users want to access their applications today. In the last decade, the technologies were adapted to this `User Centric' approach, but they still do not reach a large number of users. A necessary transformation and innovation must continue to progress! The questions that we address in this chapter are: What evolution should allow this objective? What are the fundamental novelties that would enable us to improve the agility of the network in dynamic and competitive environments? Thus, we analyze the models of: Cloud, Virtualization, Programmability and the `As a Service' model. This analysis will enable us to consider a convergent global view for the near future, with more pragmatism of the digital world to offer the hyper-connectivity desired by users.

Commoditization and virtualization of wireless networks are changing the economics of mobile networks to help network providers, e.g. Mobile Network Operators (MNOs), Mobile Virtual Network Operator (MVNO), move from proprietary and bespoke hardware and software platforms to an open, cost-efficient and flexible cellular ecosystem. In addition, rich and innovation local services can be efficiently materialized through cloudification by leveraging the existing infrastructure. The future communication architecture for mobile cloud services - Mobile Cloud Networking (MCN) is a EU FP7 large-scale integrating project (IP) funded by the European Commission that is focusing on how cloud computing and network function virtualization concepts are applied to achieve virtualization of cellular networks. It aims at the development of a fully cloud-based mobile communication and application platform, or more specifically, it aims to investigate, implement and evaluate the technological foundations for the mobile communication system of long-term evolution (LTE), based on mobile network with decentralized computing and smart storage offered as one atomic service: on-demand, elastic and pay-as-you-go. MCN will investigate, implement and evaluate the technological foundations for that system to meet real-time performance and support efficient and elastic use and sharing of radio access and mobile core network resources between operators. Mobile network functionalities-such as baseband unit processing, mobility management and quality of service (QoS) control-will run on the enhanced mobile cloud platform leveraging commodity hardware, which requires extensions toward higher decentralization and enhancing them to elastically scale up and down based on load. The end-to-end control and management orchestrates infrastructure and services across several technological domains: wireless, mobile core and data centres, providing guaranteed multiple end-to-end service, mobility through the Follow-Me Cloud concept. In this chapter, we present three enabling components of such a future MCN architecture: Radio Access Network as a Service (RANaaS), Information-Centric Networking as a Service (ICNaaS) and Mobility Prediction as a Service (MOBaaS).

Recent rapid development of both networking and cloud computing technologies is transforming the Internet from an infrastructure for data transportation to a general platform for service provisioning upon which a wide spectrum of cloud computing applications can be deployed. Such transform requires networking and cloud computing to be integrated in the next generation Internet, which calls for federated management of both networking and computing resources for service provisioning. The Service-Oriented Architecture (SOA), which has been widely adopted in cloud computing through the IaaS, PaaS, and SaaS paradigms, has been applied in networking to enable the Network-as-a-Service (NaaS) paradigm. The NaaS in networking together with IaaS in cloud computing offers a promising approach toward converged network-Cloud service provisioning in the next generation Internet. A key challenge to achieve high performance converged network-cloud services lies in composition of network and Cloud services with end-to-end performance guarantee. In this chapter, we present our recent research progress in Quality of Service (QoS)-aware network- cloud service composition, including system model and problem formulation for network-cloud service composition and our proposal of an efficient algorithm to solve this problem. We also report the experimental results for evaluating the performance of the proposed algorithm in this chapter.

This chapter focuses on conceiving a service composition framework supporting NaaS with the aid of software-defined networking. Specifically, the framework and software necessary for implementing the NaaS-enabled service composition is presented. It provides a comprehensive solution for jointly utilizing the resource of the networking and computing domain, which relies on the techniques of coordinate management, aggregation, controlling, and optimization. Then, several specific mechanisms are induced in the framework for the sake of providing multipath, multicast, and multi-domain routing service as a service component. A prototype system is constructed by integrating OpenFlow network of moderate scale and OpenStack. Experiments based on this prototype are conducted to demonstrate the applicability of the conceived framework.

Software-Defined Network (SDN) is expected to have a significant impact on future networking.Although exciting progress has been made toward realizing SDN, application of this new networking paradigm in the future Internet to support end-to-end QoS provisioning faces some new challenges. The autonomous network domains coexisting in the Internet and the diverse user applications deployed upon the Internet call for a uniform Service Delivery Platform (SDP) that enables high-level network abstraction and inter-domain collaboration for end-to-end service provisioning. However, the currently available SDN technologies lack effective mechanisms for supporting such a platform. This chapter presents an SDP framework that applies the Networkas-a-Service (NaaS) principle to provide network abstraction and orchestration for end-to-end service provisioning in SDN-based future Internet. In order to address the new challenges brought in by resource abstraction enabled by NaaS to system modeling and analysis for QoS evaluation, a profile-based analysis method developed based on the network calculus theory is also presented in this chapter.

This chapter discusses network function virtualization (NFV) to enhance flexibility and reduce costs in the deployment of service networks. NFV utilizes virtualization (e.g., virtual machines (VMs)) to separate network functions (NFs) from hardware in the form of virtual network functions (VNFs), for placement within general-purpose host machines. This makes it possible for network operators to serve a larger number of users and meet service level agreements (SLAs). This necessitates the intelligent management ofVNFs and the flow among them. Software-defined networking (SDN) is ideal for this, because the separation of control and data planes makes it possible to centralize network operations. To better understand the concept of Network as a Service (NaaS), this chapter describes how NFV works with SDN, and how the flow among service chains of VNFs in SDN networks can be managed. We outline issues crucial to the design of networks from various perspectives using a number of performance metrics. Experimental results illustrate how SLA affects network performance in NFV with SDNs. Thus, flow management for service chains of VNFs in SDNs is also covered. Two categories of orchestration mechanism in the control plane are introduced: single flow and multiple flow. We discuss latency and throughput-aware algorithms for flow management and study the problem of resource contention in datacenter networks. Finally, a summary is provided to indicate directions for future research.

In this chapter, we present a brief survey on the latest advancements in Network-as-a-Service (NaaS) platforms based on the software-defined networking (SDN) model. This survey sheds light on the main advantages of network virtualization and programmability in cloud computing environments that led to the provisioning of dynamic, flexible, and secure virtual network services. In spite of the great benefits provided by network virtualization in the cloud, further research is still needed to tackle a plethora of technical challenges in the fields of dynamic NaaS configuration and operation. This chapter paves the way for a better understanding of the problems hindering the NaaS adoption in current cloud architectures and represents a call for action on the need for having a dynamic NaaS configuration service to tackle these problems. Accordingly, the chapter proposes the design and implementation of a centralized cloud service for creating virtual networks (VNets) in SDN-based cloud architectures.

SDN is a new network operation and management solution, which decouples the control and data planes in a communication network. SDN makes it easier for network administrators to create, modify, and manage dynamic networks by abstracting low level functions and network structure. Generally, SDN uses a centralized controller, which offers a global view of the entire network. This new feature offers the flexibility for administrators to define the strategies in terms of how the network flow is forwarded on a software level. With the advancing of the research on SDN, however, distributed SDN controllers are also introduced by researchers. One reason for the emerging of distributed SDN controller is: it can address the problems of scalability, reliability, and performance issues that a centralized SDN controller suffers from acceleration

In a service ecosystem, organisations cooperate to achieve their goals. Some organisations provide application services while others consume these services, forming a web ofinterconnected services (referred to as service network). Multiple organisations or individuals (referred to as tenants) consume subsets of the services in a service network. They simultaneously share the same service network, which requires the virtualisation of the service network. The enactment and management of virtualised service networks is complex due to the heterogeneity in services, service networks, and tenants. This chapter analyses the characteristics of service networks and their virtualisation. It then presents an approach called Software-Defined Service Networking (SDSN) that applies the Network-as-a-Service (NaaS) model at the application level. This model is an abstraction of service network management functions that support the formation and management of virtualised service networks at runtime. We describe how a service network is virtualised and managed. We demonstrate the feasibility of our approach with a prototype implementation, and validate our support for the virtualisation and management of services networks.

A context-aware Internet of thing (IoT) application is a software system which utilizes various contexts acquired from IoT devices in providing context-aware functionality. The key benefit of context-aware IoT applications will be the situation-specific services provided through software analytics on the rich IoT contexts. Despite of the benefits, it is not always trivial to develop high-quality IoT applications due to the runtime overhead of acquiring and analyzing the IoT contexts. In this chapter, the potential challenges of developing context-aware IoT applications are first clarified. To address the challenges, we present Context-as-a-Service (CAAS) platform which adopts the notion of cloud computing where resources are deployed as a unit of a service. CAAS platform plays an essential role of providing contexts to IoT applications efficiently. The key design of CAAS platform and its implementation are presented in detail.